A new sediment mobility and seabed disturbance geo-spatial toolbox (Sed-mob-bed Tool)

On continental shelf seas, the spatial and temporal interaction between hydrodynamic processes and seabed substrate impacts seabed evolution and sediment distribution. For instance, when the magnitude of bed shear stress, induced by waves and/or currents, is greater than the threshold of movement, sediment is mobilised, giving rise to a range of dynamic bedforms and intricate local and regional sediment transport systems. These processes have direct implications for a wide range of offshore economic exploits (e.g., siting renewable energy and telecommunication infrastructure).

This area of research is currently at the forefront of policy and society due to the ongoing climate crisis. For instance, the Renewable Energy Directive (Directive (EU) 2023/2413) sets the European Union renewable energy target to at least 42.5 % by 2030. With offshore renewables playing a key role in reaching this objective (111 GW by 2030), the demand on the seabed is increasing. A common challenge in exploiting such offshore resources is characterising and monitoring Europe’s variable and dynamic seabed which poses significant risks to the siting and installation of engineering structures. The fiscal implications of poor background knowledge of geological and geotechnical risk before construction onset are well demonstrated by previous projects in Europe. To promote the growth of this sector in a sustainable and economically efficient manner, alongside other existing and prospective industries, the development of integrated geo-spatial tools that facilitate the interrogation of key oceanographic and geological datasets to generate standardised indicators are paramount.

To date, the characterisation and description of sediment mobilisation and seabed disturbance has been carried out using a labour and expertise intensive process. This Project will develop a ‘Sediment mobility and seabed disturbance geo-spatial toolbox (Sed-mob-bed Tool)’, a time-saving, reliable and repeatable means of qualifying and quantifying sediment mobility for a range of sediment types. This novel Sed-mob-bed Tool will facilitate the interrogation of spatial oceanographic and sedimentological datasets to produce a set of standardised sediment mobility and seabed disturbance indices (e.g., Mobilisation Frequency Index (MFI), Seabed Disturbance Index (SDI) and Sediment Mobility Index (SMI)) applicable to international end-users. Several research questions will be addressed, including:

• What are the key physical processes, sedimentological characteristics and parameters critical to sediment mobility?
• What are the most effective geospatial tools to garner this information?
• Can this be applied in a way that is geostatisically robust?
• How well do these approaches perform (i) in differing seabed morphological settings, and (ii) at scale?

The developed tool will be tested under several different environmental and seabed conditions. This includes an application to Irish Waters as a case study, leveraging the wealth of existing national and European level datasets (e.g., INFOMAR, EPA, EMODnet, GSI, Marine Institute). The results of which will be of particular interest to a cross-disciplinary group of practitioners including marine archaeologists, oceanographers, marine geoscientists, and engineers. The methodology and results from this work will ultimately provide a scientific knowledge base for the sustainable growth of the marine economy.